Method and system for providing preidentified pets selective access to a predetermined location or object

ABSTRACT

A method and system is provided that controls pet access to various different locations and/or objects. In a preferred embodiment, the present invention provides an automated system whereby pets wearing an ID tag are allowed access to various locations and/or objects, such as food contained within a feeder dish for example, while a sensor system, responding to the presence of other animals or people, causes the device to close preventing unauthorized access thereto. The feeder further includes one or more sensors using ultrasonic, infrared technology or both in combination for the identification of both tagged and non-tagged animals or children. Further embodiments employ the system to control access to litter boxes, pet toys, pet watering systems, pet gate access, pet containment systems or pet doors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 12/501,850, filed Jul. 13, 2009 and is related to and claimspriority from earlier filed U.S. Provisional Patent Application No.61/118,710, filed Dec. 1, 2008.

BACKGROUND OF THE INVENTION

The present invention relates generally to a method and system forproviding pets with controlled access to various different locationsand/or objects. More specifically, in the preferred embodiment, thepresent invention relates to an automated system whereby pets wearing anID tag are allowed access to various locations and/or objects, such asfood contained within a feeder dish for example, while a sensor system,responding to the presence of other animals or people, causes the deviceto close preventing unauthorized access thereto.

It should be noted by one skilled in the art that while the technologyof the present invention is presented in the context of a preferredembodiment pet feeder dish such disclosure is meant only to beillustrative and is not intended to limit the scope of this invention toa particular configuration. It is also intended within the scope of thepresent invention that the method and system disclosed herein can beapplied equally for controlling access to litter boxes, pet wateringsystems (including circulating and outside of the house noncirculating), pet toys, pet crates, pet gate access, pet doors, pet bedsand pet containment systems. Accordingly, the general scope of themethod and system are directed to the pet identification and accesscontrol technology and not to a specific embodiment. This provides abroad range of pet products that are improved in the context of themethod and system of the present invention.

Generally the technology disclosed herein has been discussed in theprior art only in the context of controlled access feeders. It is wellknown that some animals are restricted to certain diets for many reasonsranging from the type or breed of animal, the age of the animal, theanimal's weight or even specific health issues, such as diabetes forexample. However, it is often inconvenient based on the pet owner'sschedule to accommodate the dietary needs of the animal. This isparticularly true when the pet owner has more than one pet, eachrequiring different dietary needs. The net result is that feeding timecan become an issue for not only the pet owner but also for the petleading to further aggravation of the above listed issues and thecreation of new issues where none existed before. In addition, thepresence of young children who may try to eat pet food poses yet afurther problem for pet owners.

In an attempt to resolve these issues there is a need for a pet feedingsystem that can be set to automatically recognize and operate for aspecific pet. In response there are various types of “automatic” animalfeeding devices disclosed in the prior art. There are several devicesthat generally fall into a few distinct categories. One category ofdevices relies upon timer mechanisms that are programmed to operate on a24-hour timetable. When a predetermined elapsed time or specific clocktime is met, the device opens to allow the animal access to the food.Other devices simply depend on the pet to self regulate its consumptionof food and simply include a bulk storage device that automaticallyfills an exposed bowl by gravity feed or similar method.

Still other systems in the prior art control access to the foodcontained therein based on the presence of the pet at the feedingdevice. More particularly, as described in U.S. Pat. No. 5,570,655(Targa); and U.S. Pat. Nos. 3,897,753 and 4,036,178 (Lee et al.) acomplex control system is provided that generates an electric fieldaround an open food receptacle. An animal wearing a special collar thatis provided with a conductive portion to alter the electric fieldsignals to the system when the proper animal approaches the device. Inresponse to the signal from the proper animal, a shock or othersignal-generating device is disabled thereby allowing the proper animalto access the dish. Should an animal not wearing the special collarreach over the lip of the dish and make contact with the metallic stripthereon, the animal receives a shock that frightens the animal away fromthe dish. Alternately, instead of the conductive collar, the device canemploy radio frequency (“RF”) technology. In another alternateembodiment, upon identifying the presence of the proper animal, thedevice activates a hopper that operates to fill a food receptacle. Whilethese devices appear to have the ability to distinguish between thoseanimals entitled to access and those who are not, the use of a shock torepel an animal may be deemed to be inhumane. Further, as the food isalways exposed in the dish, this creates the risk that small children inthe household will play with or eat the pet's food. Still further, thesedevices do not solve the problem of small children or other non-taggedanimals accessing the food simultaneously in conjunction with the properanimal.

Similarly, U.S. Pat. No. 5,669,328 (Lanfranchi) provides a cone-shapeddevice that partially opens when a receiver positioned within the devicereceives a signal from a collar on a pet. There is no ability for thesystem to close should a non-tagged animal push the tagged animal awayand feed while the tagged animal remains nearby. Also, since only asmall triangular opening is provided for feeding, it is possible thatthe animal will get its head stuck in the device making it unlikely thatthe proper animal would to want to return to such a device.

U.S. Pat. No. 6,044,795 (Matsuura et al.) shows an animal tag having amemory for storing a history of the animal feeding times. The devicesamples the tag every 10 minutes and, if the animal is present,dispenses food to a separate dish. As is the case with the other priorart discussed herein, the food is exposed once dispensed, making itavailable for other animals or children to access. This device alsoappears rather complicated, especially when it is considered that it canonly feed one animal. Further, the manufacturing cost of such a deviceis greatly increased by requiring the tag to have a memory and thecontroller to interact with that memory.

U.S. Pat. No. 7,073,461 (Gonet) shows a feeder that senses all animalsand/or children proximate to the feeder, however, it does notdiscriminate between any and provides access to the food to all animalsand people. Similarly, U.S. Pat. Nos. 7,228,816 and 7,426,901 (Turner etal.) discloses a pet feeding system that also operates based onidentifying animals with tags, however, it also does not solve theissues related to non tagged animals or small children being presentwhile the tagged animal is present. In addition the system requires acomplex system for moving the food bowl from inside the feeder to theoutside. In addition the feed system can easily trap the animal as it isclosing should the pet try to keep it open.

In view of the prior art, there is a need for an automatic system thatuncovers food contained therein when the assigned pet approachesallowing the animal to eat the specific food the owner has placed inthat feeder while also recognizing all other animals in its proximity inorder to cover the food or keep it covered when those animals or peopleapproach. There is a further need for a system that excludes pets fromone feeder while allowing access to yet another feeder so that they maybe able to eat the food they require. Still further there is a need fora simplified pet feeding system that controls access by a plurality ofanimals to food, which can provide the correct food safely to thecorrect animal and is relatively less complex and cost-effective inregard to its use and operation.

Alternately there is a need for applying this identification and accesscontrol technology to litter boxes where there is a need to prevent dogsand small children from getting into cat litter boxes. Litter boxes areby nature not a clean environment. The possibility that children orother household pets such as dogs may enter a litter box represents ahealth hazard to the children of families with cats. To date litter boxprior art is limited to varying techniques for cleaning the litter boxesof clumped litter and other waste products, not to the health issuesassociated with this dirty environment and the free access all creatureshave to these products.

Still further there remains an alternate need to apply theidentification and access control technology to pet watering systemsincluding circulating and outside of the house non circulating, pettoys, pet crate and gate access, pet doors, pet beds, and petcontainment systems. These products can all be significantly improvedfrom the addition of this technology resulting in improved health andsafety of both pets and family members for households with pets.

BRIEF SUMMARY OF THE INVENTION

In this regard, the present invention provides a method and systemprovided that controls pet access to various different locations and/orobjects. More specifically, in a preferred embodiment, the presentinvention provides an automated system whereby pets wearing an ID tagare allowed access to various locations and/or objects, such as foodcontained within a feeder dish for example, while a sensor system,responding to the presence of other animals or people, causes the deviceto close preventing unauthorized access thereto.

In a first embodiment, the present invention is disclosed as a singlebowl pet feeder. Generally the feeder includes a body or housing thathas a door guide track therein and a food bowl located in the interiorof the body. During normal operation the door in the guide track isclosed thereby covering the food bowl making it inaccessible to eitheranimals or small children. The feeder further includes one or moresensors on the top and/or front face for the identification of bothtagged and non-tagged animals or children. Preferably the sensorsfunction using RFID technology, ultrasonic, infrared technology orcombinations thereof to verify that there is only the target or approvedanimal in close proximity to the feeder.

In operation, as a tagged pet approaches the feeder, one sensoridentifies if the tag is authorized. If the tag is authorized orapproved, the door opens to allow the pet access to the food containedtherein. When the tagged pet departs, the door closes preventing accessto the food. In contrast to the prior art, the present invention alsoemploys additional sensors to determine the presence of other non-taggedanimals or children. Should such a presence be detected (even when aauthorized tagged pet is accessing the feeder) the door is closedthereby preventing a non-tagged animal or child from accessing the foodcontemporaneously with the tagged pet. In addition, should a nonauthorized tagged pet approach the feeder the sensors will pick up thatand will close the door.

It is also within the scope of this invention that sensors alone beemployed to identify the target animal as contrasted to the non-targetpet or person. In this regard, the sensors will identify the visible,infrared or ultrasonic signature of the target animal and only operatewhen that signature is detected. The approved “signature” data isprogrammed into the feeder control at first set-up. Additional and/ornon-matching signatures will cause device to close. As was stated abovethis pet identification technology is also disclosed in an alternateembodiment in the context of litter boxes. Another embodiment disclosespet watering systems including circulating and outside of the house noncirculating watering dishes. Still a further embodiment depicts pet gateaccess, pet containment systems or pet doors. All totaled the petidentification and access control technology can be applied across abroad range of pet products.

It is therefore an object of the present invention to provide anautomatic system that uncovers food contained therein when the assignedpet approaches allowing the animal to eat the specific food the ownerhas placed in that feeder while also recognizing all other animals inits proximity in order to cover the food or keep it covered when thoseanimals or people approach. It is a further object of the presentinvention to provide a system that excludes pets from one feeder whileallowing access to yet another feeder so that they may be able to eatthe food they require. It still a further object of the presentinvention to provide a simplified pet feeding system that controlsaccess by a plurality of animals to food, which can provide the correctfood safely to the correct animal and is relatively less complex andcost-effective in regard to its use and operation. It is yet a furtherobject of the present invention to provide a system that providesselective control and access to other pet related items such as litterboxes, pet watering systems including circulating and outside of thehouse non circulating, pet toys, pet crate and gate access, pet doors,pet beds, and pet containment systems.

These together with other objects of the invention, along with variousfeatures of novelty that characterize the invention, are pointed outwith particularity in the claims annexed hereto and forming a part ofthis disclosure. For a better understanding of the invention, itsoperating advantages and the specific objects attained by its uses,reference should be had to the accompanying drawings and descriptivematter in which there is illustrated a preferred embodiment of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings which illustrate the best mode presently contemplatedfor carrying out the present invention:

FIG. 1 is a front perspective view of a pet feeding dish in accordancewith the teachings of the present invention;

FIG. 2 is a front, exploded perspective view of the pet feeding dish ofFIG. 1;

FIG. 3 is a perspective view of the controlled access portion of the petfeeding dish of FIG. 1;

FIG. 4 is an exploded perspective view of the controlled access portionof FIG. 3;

FIG. 5 is a representation of the various fields of view of the sensorsemployed in the system of the present invention;

FIG. 6 is a flow chart describing the operation of the system of thepresent invention;

FIG. 7 is a perspective view of an alternate embodiment of the presentinvention in the context of a pet door;

FIG. 8 is a perspective view of an alternate embodiment of the presentinvention in the context of a litter box; and

FIG. 9 is a perspective view of an alternate embodiment of the presentinvention in the context of a watering dish.

DETAILED DESCRIPTION OF THE INVENTION

Now referring to the drawings, a method and system is provided thatcontrols pet access to various different locations and/or objects andmore specifically, in the preferred embodiment, as depicted at FIGS.1-4, provides an automated system whereby pets wearing an authorized IDtag are allowed access to various locations and/or objects, such as foodcontained within a feeder dish for example, while a sensor system,responding to the presence of other animals or people, causes the deviceto close preventing unauthorized access thereto. Pets wearing anon-authorized ID tag also cause the device to close preventingunauthorized access thereto.

In the most general embodiment of the present invention, a system isprovided for controlling pet access to locations or objects. The systemincludes a location or object to be controlled, a means for preventingpet access to said location or object and a sensor system configured andarranged to selectively disengage the means for preventing pet access.The sensor system includes at least one tag that provides authorizationto access the location or object wherein the at least one tag ispreferably disposed on an authorized pet, a first sensor for controllingpet access by detecting the presence of the tag and disengaging themeans for preventing pet access and a second sensor that detects thepresence of an animal other than the authorized pet and engaging themeans for preventing pet access.

It should be noted by one skilled in the art that while the technologyof the present invention is presented most generally as a system forcontrolling pet access to locations or objects and that the invention isillustrated in the context of several preferred embodiments, suchdisclosure is meant only to be illustrative and is not intended to limitthe scope of this invention to a particular configuration. It is alsointended within the scope of the present invention that the method andsystem disclosed herein can be applied equally for controlling access tolitter boxes, pet watering systems (including circulating and outside ofthe house non circulating), pet toys, pet crates, pet gate access, petdoors, pet beds and pet containment systems. Accordingly, the generalscope of the method and system are directed to the pet identificationand access control technology and not to a specific embodiment. Thisprovides a broad range of pet products that are improved in the contextof the method and system of the present invention.

Turning now to FIG. 1, the method and system of the present invention isspecifically illustrated in the context of a pet feeder dish 10. Thefeeder dish 10 can be seen to include a housing 12 with a base portion14 that includes a compartment 16 therein and electronics 18 forcontrolling the overall system. One or more sensors 20 can also be seenon the face of this base portion 14. The sensors 20 operate, as will bedescribed in greater detail below, for the identification of both taggedand non-tagged animals or children. Preferably the sensors 20 functionusing ultrasonic, infrared technology or both in combination to verifythat there is only the target or approved animal in close proximity tothe feeder. In addition, electronic controls 18 are shown that includeprogramming capability that may include a user interface including butnot limited to buttons, switches and/or a liquid crystal display (LCD).A second compartment 22 can be seen on top of and extending upwardlyfrom the base portion 14. The second compartment 22 is optionallyprovided as a food storage region so that rather than operate as asingle feeding device, the feeder 10 can be operated on a controlledbasis by dispensing food over a number of days with out needing to berefilled. Additionally, a means for controlling access to the foodcompartment can be seen in the form of a door 24. While a sliding door24 is depicted herein, one skilled in the art can appreciated that thedoor may take any number of forms including but not limited to a slidingdoor, a hinged door that swings in or out, a rotary door, a pivotingdoor, a door that is displaced vertically or horizontally or anycombination of the above functions. The only limitation is that the door24 serves as a means to restrict and control access to the foodcontained within the compartment 16 in the housing 12.

An exploded view of the pet feeder 10 can be seen at FIG. 2. In thisfigure the housing 12 can be seen to enclose a removable dish 26 withinthe means for controlling access 16. Further, the second uppercompartment 22 can also be seen to be removable thereby allowing easyremoval and cleaning of these components as they directly contact andhouse the pet food. Further, the housing 12 encloses a dispensingassembly 28 that is formed with the means for controlling access 16.This dispensing assembly 28 is shown to be formed as a single unit withthe means for controlling access to facilitate manufacturing resourcesand costs although both assemblies may be made separate and apart fromone another.

FIGS. 3 and 4 provide a detailed illustration of the dispensing assembly28 and the means for controlling access to the compartment containingthe food dish 26. The door 24 is shown as being retractable and ispreferably a segmented type door that allows it to slide freely within atrack 30. This arrangement allows easy opening and closing of the door24. Such operation is controlled by various motor 32 and gear 34arrangements as are well known in the art. The notable features of theoperation of the means for controlling access is that the operation ofthe control feature is controlled in such a way as to prevent a pet frombeing trapped. In this manner, if a pet gets caught by the door 24, itwill pause to release the pet yet still try to close in a manner thaturges the pet away from the compartment. Further, in this particulararrangement the door 24 slides from the lower front of the device to theupper rear of the device in a manner that nudges the pet out of the fooddish 26. The food dispensing assembly 28 is operative to transport foodfrom the food storage compartment 22 to the food dish 26 based oncommands issued by the controls 18. The timing and frequency of thisdispensing operation can widely vary and is not considered part of or alimitation on the present disclosure. Further, while a conveyor isdepicted as a food dispensing assembly 28, various door, gate,rotational drums, hoppers and cup arrangements could also be used andstill fall within the scope of the present invention. Visible lightsensing and other sensors known to those skilled in the art are alsopotential technologies that may be employed to identify both tagged andnon-tagged animals or children.

Generally, as can be seen at FIG. 3, the door 24, which is shown in aclosed position thereby covering the food dish 26, making itinaccessible to either animals or small children. Not shown is an override switch witch is used by the owner to open the feeder for bowlfilling and removal for cleaning. Additionally, the feeder includes oneor more sensors 20 on the top and/or front face for the identificationof both tagged and non-tagged animals or children. Preferably thesensors function using ultrasonic, infrared technology or both incombination to verify that there is only the target or approved animalin close proximity to the feeder.

In operation, as was stated above, the feeder 10 may employ infrared andultrasonic sensors on their own or may employ in combination an RF ormagnetic sensor that determines the presence of an authorized tag. A tagis established as authorized or non-authorized at initial set up of thelogic system. It is important to note that the infrared and/orultrasonic sensors are arranged to detect a plurality of discrete zones36, 28, 40. One possible arrangement of the sensors 20 is depicted atFIG. 5. In particular, this embodiment depicts three separate sensorsthat respectively cover left 36, center 40 and right 38 zones relativeto the device. Further, each of the sensors 20 is capable of discretelydetecting input across a plurality of vertical heights relative to thebase of the feeder. In other words, the left sensor can sense at severaldifferent vertical bands 36 a, b, c, d, the center sensor can sense atseveral different vertical bands 40 a, b, c, d and the right sensor cansense at several different vertical bands 38 a, b, c, d. Thisarrangement would be similar regardless of the number and positioning ofthe sensors 20. By creating an array of sensors 20 in this manner, thedevice can collect information in order to assess the size of the animaltrying to access the device, the number of separate animals present atthe device and the general movement and direction of any animal(s)present. By applying logic to the collected sensor 20 input, the devicecan determine whether the only animal present is the authorized animalor if another animal is trying to access the device thereby triggeringit to close.

As is depicted at the flow chart at FIG. 6, in operation, as a taggedpet approaches the feeder, the system determines if the tag isauthorized 42. If an authorized tag is present, the door opens to allowthe pet access to the food contained therein 44. If the sensorsdetermine that there is movement in one of the adjacent sensor zones 46the system assesses whether the animal present is moving toward or awayfrom the feeder 48. If the animal is moving away the feeder closes thedoor 50. On the other hand, if the animal is moving toward the feeder,the feeder polls for tags in the vicinity 52. If the tag is authorized42, the feeder remains open 44, if there is no tag present or if the tagis not authorized, the feeder closes 50. Further, if the sensors detectanimals in adjacent zones trying to access the feeder simultaneously 54with the animal bearing the authorized tag, the door closes regardlessof the presence of the animal with the authorized tag in order toprevent access by the non-authorized animal.

It is also within the scope of this invention that sensors alone beemployed to identify the target animal as contrasted to the non-targetpet or person. In this regard, the sensors will identify the visible,infrared or ultrasonic signature of the target animal and only operatewhen that authorized signature is detected, additional or non-authorizedsignatures will cause device to close. The authorized signature isstored in the systems logic controller at initial set up.

Turning now to FIG. 7, an alternate embodiment is provided that depictsthe teachings of the present invention in the context of a pet accessdoor 100. The pet door 100 includes a frame 102 that is configured to beinstalled into an opening in a door or wall. A door 104 is providedwithin the frame 102 and serves as the means for preventing access. Thedoor 104 is freely displaceable by an animal to an open position when afirst sensor 120 detects the presence of said at least one authorizedtag. However the door 104 is latched in a closed position when one ofthe other sensors 120 detects the presence of an animal other than theanimal bearing the authorized tag. As was the case above, should thesecond sensor 120 detect the presence of an animal other than theauthorized pet, the door 104 remains latched or closes even if the firstsensor 120 detects the presence of the authorized tag.

FIG. 8 depicts another an alternate embodiment in the context of alitter box 200. The litter box 200 also has a housing 212 with acompartment 216 therein. In this case the compartment 216 is a littercompartment. The means for preventing access is a door 224 that movesbetween an open position when said first sensor 220 detects the presenceof said at least one authorized tag and a closed position when saidsecond sensor 220 detects the presence of an animal other than theauthorized pet. This system can be used in conjunction with knownmethods of odor and/or waste elimination.

In still a further embodiment, FIG. 9 depicts the teachings of thepresent invention in the context of a pet watering device 300. Much inthe same manner as described above, with respect to the feeder, the petwatering device 300 includes a housing 312 with a base portion 314 thatincludes a compartment 316 therein and electronics 318 for controllingthe overall system. One or more sensors 320 can also be seen on the faceof this base portion 314. In addition controls are shown that includeprogramming capability that may include a user interface including butnot limited to buttons, switches and/or a liquid crystal display (LCD).A second compartment 322 can be seen on top of and extending upwardlyfrom the base portion 314. The second compartment 322 is provided aswater reservoir region. Additionally, a means for controlling access tothe water compartment 316 can be seen in the form of a door 324. Thedoor 324 moves between an open position when said first sensor 320detects the presence of said at least one authorized tag and a closedposition when said second sensor 320 detects the presence of an animalother than the authorized pet. This system can be used in conjunctionwith known methods of water filtration.

It can therefore be seen that the present invention provides anautomatic system that provides selective control and access to othervarious locations and objects such as pet related items like feeders,litter boxes, pet watering systems including circulating and outside ofthe house non circulating, pet toys, pet crate and gate access, petdoors, pet beds, and pet containment systems in a relatively lesscomplex and cost-effective in regard to its use and operation. For thesereasons, the present invention is believed to represent a significantadvancement in the art, which has substantial commercial merit.

While there is shown and described herein certain specific structureembodying the invention, it will be manifest to those skilled in the artthat various modifications and rearrangements of the parts may be madewithout departing from the spirit and scope of the underlying inventiveconcept and that the same is not limited to the particular forms hereinshown and described except insofar as indicated by the scope of theappended claims.

1. A method of controlling pet access to locations comprising:determining a location to be controlled; providing a means forpreventing pet access to said location or object; and selectivelydisengaging said means for preventing pet access via a sensor systemcomprising: a first sensor within said means for preventing pet access,said first sensor detecting the presence of said at least one authorizedpet and disengaging said means for preventing pet access; a secondsensor within said means for preventing pet access, said second sensordetecting the presence of an animal other than said authorized pet andengaging said means for preventing pet access.
 2. The method of claim 1,wherein said location to be controlled is selected from the groupconsisting of: pet feeders, litter boxes, pet watering systems, pet gateaccess, pet containment systems and pet doors.
 3. The method of claim 1,wherein said first and second sensors are selected from the groupconsisting of: infrared sensors, ultrasonic sensors and combinationsthereof.
 4. The method of claim 1, wherein said means for preventingaccess is engaged when said second sensor detects the presence of ananimal other than said authorized pet even if said first sensor detectsthe presence of said at least one tag.
 5. The method of claim 1, whereinsaid second sensor is an infrared sensor.
 6. The method of claim 1,wherein said second sensor is an ultrasonic sensor.
 7. The method ofclaim 1, wherein said location to be controlled is a pet feeding dishcompartment further comprising: a housing with a compartment therein; adish for containing food disposed within said compartment; said meansfor preventing access being a door that moves between an open positionwhen said first sensor detects the presence of said at least one tag anda closed position when said second sensor detects the presence of ananimal other than said authorized pet.
 8. The method of claim 7, whereinsaid door is closed when said second sensor detects the presence of ananimal other than said authorized pet even if said first sensor detectsthe presence of said at least one tag.
 9. The method of claim 1, whereinsaid location to be controlled is a pet feeding dish compartment furthercomprising: a housing including a feeding compartment, a food storagecompartment and a means for selectively transporting food from saidstorage compartment to said feeding compartment; a dish for containingfood disposed within said feeding compartment; said means for preventingaccess being a door that moves between an open position when said firstsensor detects the presence of said at least one tag and a closedposition when said second sensor detects the presence of an animal otherthan said authorized pet.
 10. The method of claim 9, wherein said dooris closed when said second sensor detects the presence of an animalother than said authorized pet even if said first sensor detects thepresence of said at least one tag.
 11. The method of claim 1, whereinsaid location to be controlled is a litter box compartment furthercomprising: a housing including a litter compartment; said means forpreventing access being a door that moves between an open position whensaid first sensor detects the presence of said at least one tag and aclosed position when said second sensor detects the presence of ananimal other than said authorized pet.
 12. The method of claim 11,wherein said door is closed when said second sensor detects the presenceof an animal other than said authorized pet even if said first sensordetects the presence of said at least one tag.
 13. The method of claim1, wherein said location to be controlled is a pet door opening furthercomprising: a frame configured to be installed into an opening in a dooror wall; said means for preventing access being a door that is freelydisplaceable to an open position when said first sensor detects thepresence of said at least one tag and is latched in a closed positionwhen said second sensor detects the presence of an animal other thansaid authorized pet.
 14. The method of claim 13, wherein said door islatched when said second sensor detects the presence of an animal otherthan said authorized pet even if said first sensor detects the presenceof said at least one tag.